Composite sintered body, honeycomb structure, electrically heating catalyst, and method of manufacturing composite sintered body

Abstract

A composite sintered body contains a silicon phase, a cordierite phase, and a high-resistance silicon carbide phase. The content of silicon in the composite sintered body to the composite sintered body is not lower than 30 mass % and not higher than 50 mass %. The content of cordierite in the composite sintered body to the composite sintered body is not lower than 10 mass % and not higher than 50 mass %. The content of high-resistance silicon carbide in the composite sintered body to the composite sintered body is not lower than 20 mass % and not higher than 50 mass %.

1 . A composite sintered body, containing:
 a silicon phase;   a cordierite phase; and   a high-resistance silicon carbide phase,   wherein the content of silicon in said composite sintered body to said composite sintered body is not lower than 30 mass % and not higher than 50 mass %,   the content of cordierite in said composite sintered body to said composite sintered body is not lower than 10 mass % and not higher than 50 mass %, and   the content of high-resistance silicon carbide in said composite sintered body to said composite sintered body is not lower than 20 mass % and not higher than 50 mass %.   
     
     
         2 . The composite sintered body according to  claim 1 , wherein
 a median diameter of silicon particles, based on a volume standard, in said composite sintered body is not smaller than 9 μm.   
     
     
         3 . The composite sintered body according to  claim 1 , wherein
 a porosity of said composite sintered body is not lower than 30% and not higher than 50%.   
     
     
         4 . The composite sintered body according to  claim 1 , wherein
 an average pore diameter of said composite sintered body is not smaller than 2.5 μm and not larger than 4.0 μm.   
     
     
         5 . The composite sintered body according to  claim 1 , wherein
 a volume resistivity of said composite sintered body at 20° C. is not lower than 1.0Ω·cm and not higher than 100Ω·cm.   
     
     
         6 . The composite sintered body according to  claim 1 , wherein
 a change rate of a volume resistivity of a composite sintered body after exposing said composite sintered body to an atmosphere at 950° C. for 50 hours is not higher than 100%.   
     
     
         7 . The composite sintered body according to  claim 1 , wherein
 the content of low-resistance silicon carbide in said composite sintered body to said composite sintered body is not higher than 1 mass %.   
     
     
         8 . A honeycomb structure, comprising:
 a cylindrical outer wall; and   a lattice partition wall partitioning an inside of said outer wall into a plurality of cells,   wherein said outer wall and said partition wall are formed, including said composite sintered body according to  claim 1 .   
     
     
         9 . An electrically heating catalyst used for performing a purification treatment of exhaust gas discharged from an engine, comprising:
 said honeycomb structure according to  claim 8 ; and   a pair of electrode terminals fixed to an outer surface of said honeycomb structure, for giving a current to said honeycomb structure.   
     
     
         10 . A method of manufacturing a composite sintered body, comprising:
 a) obtaining a green body by molding raw material powder containing a silicon raw material, a cordierite raw material, and a high-resistance silicon carbide raw material; and   b) obtaining a composite sintered body by sintering said green body,   wherein said composite sintered body contains   a silicon phase;   a cordierite phase; and   a high-resistance silicon carbide phase,   and wherein the content of silicon in said composite sintered body to said composite sintered body is not lower than 30 mass % and not higher than 50 mass %,   the content of cordierite in said composite sintered body to said composite sintered body is not lower than 10 mass % and not higher than 50 mass %, and   the content of high-resistance silicon carbide in said composite sintered body to said composite sintered body is not lower than 20 mass % and not higher than 50 mass %.   
     
     
         11 . The method of manufacturing a composite sintered body according to  claim 10 , wherein
 a sintering shrinkage of said composite sintered body to said green body is not higher than 7%.